A couple days ago, I noticed a couple of my year-old hens were periodically making a noise that sounded like a honking hiccup sneeze (that's the only way I can describe it). I only noticed it in the morning, but I'm not out with them all day, and it seemed worse when they bent to eat and drink. They are stretching their necks out and shaking their heads. Combs seem pale, but I don't see any body parasites, they are laying, and eating and drinking. Anyway, this morning half my flock is doing it. First I was thinking gape worm, but does it spread that quickly from one to the next? Are there any diseases with these symptoms?